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authorstephen hemminger <shemminger@vyatta.com>2009-11-11 07:40:36 +0000
committerDavid S. Miller <davem@davemloft.net>2009-11-11 19:22:18 -0800
commite5c140a340c4796054b0f6e9035e1faa7edfa6d6 (patch)
treeca150ab28a91eba36838ffc1519840fac705aa82 /net/decnet
parent41bdecf17e6dba92256c65972ec79a482d978be5 (diff)
downloadlinux-e5c140a340c4796054b0f6e9035e1faa7edfa6d6.tar.bz2
decnet: convert dndev_lock to spinlock
There is no reason for this lock to be reader/writer since the reader only has lock held for a very brief period. The overhead of read_lock is more expensive than spinlock. Compile tested only, I am not a decnet user. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/decnet')
-rw-r--r--net/decnet/dn_dev.c19
1 files changed, 12 insertions, 7 deletions
diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
index 5790d660bc7d..6c916e2b8a84 100644
--- a/net/decnet/dn_dev.c
+++ b/net/decnet/dn_dev.c
@@ -68,7 +68,7 @@ extern struct neigh_table dn_neigh_table;
*/
__le16 decnet_address = 0;
-static DEFINE_RWLOCK(dndev_lock);
+static DEFINE_SPINLOCK(dndev_lock);
static struct net_device *decnet_default_device;
static BLOCKING_NOTIFIER_HEAD(dnaddr_chain);
@@ -557,7 +557,8 @@ rarok:
struct net_device *dn_dev_get_default(void)
{
struct net_device *dev;
- read_lock(&dndev_lock);
+
+ spin_lock(&dndev_lock);
dev = decnet_default_device;
if (dev) {
if (dev->dn_ptr)
@@ -565,7 +566,8 @@ struct net_device *dn_dev_get_default(void)
else
dev = NULL;
}
- read_unlock(&dndev_lock);
+ spin_unlock(&dndev_lock);
+
return dev;
}
@@ -575,13 +577,15 @@ int dn_dev_set_default(struct net_device *dev, int force)
int rv = -EBUSY;
if (!dev->dn_ptr)
return -ENODEV;
- write_lock(&dndev_lock);
+
+ spin_lock(&dndev_lock);
if (force || decnet_default_device == NULL) {
old = decnet_default_device;
decnet_default_device = dev;
rv = 0;
}
- write_unlock(&dndev_lock);
+ spin_unlock(&dndev_lock);
+
if (old)
dev_put(old);
return rv;
@@ -589,13 +593,14 @@ int dn_dev_set_default(struct net_device *dev, int force)
static void dn_dev_check_default(struct net_device *dev)
{
- write_lock(&dndev_lock);
+ spin_lock(&dndev_lock);
if (dev == decnet_default_device) {
decnet_default_device = NULL;
} else {
dev = NULL;
}
- write_unlock(&dndev_lock);
+ spin_unlock(&dndev_lock);
+
if (dev)
dev_put(dev);
}